Explosives Detection with Nuclear Quadrupole Resonance

The phenomenon of nuclear quadrupole resonance is akin to nuclear
magnetic resonance, which is the basis of magnetic-resonance
imaging. But unlike MRI scanners, instruments based on nuclear
quadrupole resonance are not required to generate strong magnetic
fields. This technique is thus suitable for detecting land mines, an
application for which it would be difficult to project a uniform
magnetic field into the ground. Although many different technical
measures are available to search for land mines and other kinds of
hidden explosives (including trained dogs, electronic metal
detectors and ground-penetrating radar), instruments based on
nuclear quadrupole resonance offer some special advantages. In
particular, they are highly discriminating, being able to sense the
presence of various nitrogen-rich compounds used in explosives.
Nuclear quadrupole resonance offers the possibility of being applied
to other tasks as well, including the nondestructive evaluation of materials.